When one update arrives at the monitor and the server delivering the update becomes idle, we introduce a fake update to the server using the method introduced in [1]}.
Thus we can reduce the calculation complexities and only have one discrete state indicating that all servers are virtually busy. We denote this state by \(q=0\) .
In particular, we put the current update that is in the monitor to an idle server until the next update reaches this server. This assumption does not affect our final calculation for AoI, because even if the fake update is delivered to the monitor, AoI at the monitor does not change. Moreover, serving the fake update does not affect the service of future actual updates because of preemption in service.
